Margarita Peak
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Margarita Peak   Elev. 3189 ft.
© W.P. Armstrong, 20 November 2007
Arduous Hike To The Summit

Tom, James & Mike hiking up steep, rocky firebreak.

Views Looking East & North From Steep Firebreak

Coastal San Diego County & Dense Marine Layer.

Grassland summit of Miller Mountain (Elev. 2953 feet) surrounded by dark green chaparral. The
Santa Rosa basalt brodiaea (Brodiaea santarosae) is abundant on basalt in the grassland area.

Views Looking West From Summit Ridge

Grassland & oak woodland of Camp Pendleton.

Case Springs at Camp Pendleton.

Rock Types On Margarita Peak

A. Santiago Peak Volcanic from summit of Owens Peak in San Marcos, San Diego County.
B. Santiago Peak Volcanic from the east side of Margarita Peak near Roblar Creek.

Rock from summit ridge of Margarita Peak that is colonized by lichens. The weathered rock is reddish with many surface pits. The pitted surface shows better in the next image. The rock is quartz-bearing diorite similar to tonalite. It is not San Marcos Gabbro.

Lichens prefer the pitted, weathered surface of this quartz-bearing diorite.

Foliose rock lichen Xanthoparmelia mexicana, an isidiate species without apothecia. The dark areas of thallus are covered with numerous pimplelike projections called isidia. The isidia contain algae and fungi and readily become detached and dispersed to new locations. Another common species (X. cumberlandia) has prominent, cup-shaped apothecia but lacks isidia. The pitted rock in photo is quartz-bearing diorite.

See The Isidia Of Xanothoparmelia mexicana
  Apothecia Of Xanothoparmelia cumberlandia  
A List Of Lichen Images On Wayne's Word

Boulder and reddish soil on west side of summit ridge. The rock is quartz-bearing diorite similar to tonalite. The reddish soils come from ferro-magnesium minerals in the rock. It is not San Marcos Gabbro. Compare this rock with true San Marcos Gabbro in the next image.

San Marcos Gabbro from the southern Merriam Mountains in San Diego County.

  See San Marcos Gabbro In The San Marcos Mts.  
Woodson Mt. Granodiorite In The Merriam Mts.
Santiago Peak Metavolcanic On Owens Peak